1. Field of Invention
The present invention relates in general to a detector and a method of producing same and more particularly to a rotation detecting device that detects a rotation speed of a rotation member and a method of producing same.
2. Description of Related Art
Hitherto, as rotation detecting devices, optical and magnetic types have been widely used because these types can detect a rotation speed of a rotation member without contacting the same.
Laid-open Japanese Patent Application (Tokkai) 2000-180460 shows a magnetic type rotation detecting device that detects rotation speed of an automotive road wheel. In the device of this publication, there is used a substrate of insulated plastic material for mounting thereon a given wiring pattern. The plastic material has glass fibers embedded therein for a reliable durability of the substrate. To the substrate, there are further connected through soldering various electronic elements, such as, a magnetic resistance element, Hall element and the like for a sensor. The substrate thus mounting thereon the various electronic elements is installed in a metal case which is fixed to a housing of plastic material.
Laid-open Japanese Patent Application (Tokkai-hei) 11-14644 shows, as is seen from FIGS. 12 and 13 of the accompanying drawings, a substrate 52 (see FIG. 13) which is received in a recess 50A formed in a housing 50 of plastic material. As is seen from FIG. 12, a plastic sealing material 54 is packed in recess 50A to hermetically install substrate 52 in recess 50A. The housing 50 has a connector part 56 integrally molded therewith with terminal pins 56A (only one is shown) as inserts. For assembling the parts, substrate 52 is set in the recess 50A, then, terminal pins 56A are soldered to given portions of a wiring pattern on substrate 52, and then, plastic sealing material 54 is packed in recess 50A.
However, the rotation detecting devices of the above-mentioned publications have failed to provide users with satisfaction. Specifically, due to inherent constructions, production of the devices needs a complicated assembling process which thus brings about increase in cost of the devices.
It is therefore an object of the present invention to provide a rotation detecting device which is easily produced and assembled.
It is another object of the present invention to provide a method of producing the rotation detecting device with ease.
According to a first aspect of the present invention, there is provided a rotation detecting device which comprises an intermediate assembly including terminal pins having given portions, each given portion having at least one projection; a molded plastic base in which the given portions of the terminal pins are embedded with the projections being exposed to the outside; and a plurality of electronic elements connected to the exposed projections of the given portions of the terminal pins, one of the electronic elements being a sensor element which is mounted on the molded plastic base; and a molded plastic housing entirely and hermetically covering the intermediate assembly except a connector part thereof where leading ends of the terminal pins are positioned.
According to a second aspect of the present invention, there is provided a method of producing a rotation detecting device, which comprises (a) setting a plurality of terminal pins in a first mold assembly, the terminal pins having projections; (b) injecting a molten plastic material into the first mold assembly to produce a parts-holder, the parts-holder including a molded plastic base in which given portions of the terminal pins are embedded with the projections being exposed to the outside; (c) connecting electronic elements to the exposed projections of the terminal pins thereby to constitute an intermediate assembly; and (d) molding a housing that hermetically embeds therein the intermediate assembly except leading ends of the terminal pins and has a recess of a connector part to which the leading ends of the terminal pins are exposed.
According to a third aspect of the present invention, there is provided a method of producing a rotation detecting device, which comprises (a) setting a plurality of terminal pins in a first mold assembly, the terminal pins having projections; (b) injecting a molten plastic material into the first mold assembly to produce a parts-holder, the parts-holder including a molded plastic base in which given portions of the terminal pins are embedded with the projections being exposed to the outside; (c) connecting electronic elements to the exposed projections of the terminal pins thereby to constitute an intermediate assembly, the connecting being achieved by one of soldering technique and welding technique; (d) setting the intermediate assembly in a second mold assembly; and (e) injecting a molten plastic material into the second mold assembly to mold a housing that hermetically embeds therein the intermediate assembly except leading ends of the terminal pins and has a recess of a connector part to which the leading ends of the terminal pins are exposed.
According to a fourth aspect of the present invention, there is provided a method of producing a rotation detecting device, which comprises (a) setting a plurality of terminal pins in a first mold assembly, the terminal pins having projections; (b) injecting a molten plastic material into the first mold assembly to produce a parts-holder, the parts-holder including a molded plastic base in which given portions of the terminal pins are embedded with the projections being exposed to the outside; (c) connecting electronic elements to the exposed projections of the terminal pins thereby to constitute a first intermediate assembly, the connecting being achieved by one of soldering technique and welding technique; (d) setting the first intermediate assembly in a second mold assembly; (e) injecting a molten plastic material into the second mold assembly to mold a first housing part that hermetically embeds therein the first intermediate assembly except leading portions of the terminal pins, thereby to produce a second intermediate assembly; (f) setting the second intermediate assembly in a third mold assembly; and (g) injecting a molten plastic material into the third mold assembly to mold a second housing part that hermetically covers one portion of the second intermediate assembly and has a recess of a connector part to which leading ends of the terminal pins are exposed.